The present invention relates to a vehicle suspension assembly, and in particular to a heavy-duty suspension system with increased roll stability and resistance to lateral deflection.
A variety of suspensions utilizing air springs have been developed for use within semi-tractor trailer and other heavy vehicles. These systems control the relative position of the chassis with respect to an associated axle and also to cushion the relative movement of the axle toward the chassis frame. While these systems provide superior cushioning of the chassis over a wide variety of chassis or vehicle loads, conventional air springs by themselves do not typically develop acceptable resistance to vehicle roll, such as experienced when the vehicle negotiates a turn, nor a resistance to lateral shifting of the vehicle, such as experienced during acceleration and deceleration. In general, the lower the spring rate, the greater the cushioning effect, and the lower the roll and lateral shift resistance. Conversely, the higher the spring rate, the higher the roll and lateral shift resistance. While leaf spring suspensions provide adequate roll resistance, they do not provide the same degree of cushions as do air spring systems, particularly when the vehicle is empty or carrying a light load. The rough ride experienced with a leaf spring suspension at low vehicle loads can contribute to cargo and trailer damage as well as human discomfort.
Heretofore, specialized components have been added to air spring systems to reduce roll and lateral shift. However, many of these components add significant weight and cost to the associated suspension system without greatly reducing the roll and lateral shift. Torqueing of the wheel axles has also been utilized to develop roll resistance, however, this solution can sometimes lead to axle failure.
There is a need for a lightweight and inexpensive air spring suspension system that resists roll and lateral shift that will not significantly impact the ride-cushioning characteristics of such suspension system.